That's right, the 1400 is, indeed, a two stage pump and I have 3 of them now. With a good long pump down to clear the initial moisture, I pulled my first large demo fusor down to 16 micorons with this little pump.
It might be noted to vacuum newbies that pumping for hours and days on end will accomplish little, bottom end pressure wise, unless your system is loaded with moisture. There is a point in a clean, dry system being pumped without a trap, that the oil in the pump gets so hot that it is the fouling and limiting factor in further pump down.
With a good trap on the mechanical pump foreline, (Lesker micromaze) I have pumped my system to 10e-4 torr or 0.1 micron! This was using a precision 6cfm belt driven pump I have of fusor III.
This trap is not nearly as important if you are using a diff pump or turbopump to reach high vacuums. If you are only mechanically pumping, however, a well cared for trap is a God send and near necessity.
Richard Hull
Created on Friday, January 05, 2001 12:53 PM EDT by Richard Hull